Sonic Waves Research Articles

Intravascular lithotripsy in the management of underexpanded stents

Abstract Introduction Stent underexpansion significantly heightens the risk of major adverse cardiac events (MACE), and available treatment options for this condition remain limited. Intravascular Lithotripsy (IVL) technology disrupts superficial and deep calcium by using localized pulsative sonic pressure waves, emerges as a promising tool for underexpanded stents. Methods Following PRISMA guidelines, we systematically explored PubMed, SCOPUS, and Cochrane databases up to September 3, 2023, for studies evaluating IVL's safety and efficacy in treating underexpanded stents. We gathered angiographic (QCA) and intracoronary imaging (OCT or IVUS) data, examining the stent's minimal diameter stenosis (MDS), minimal lumen diameter (MLD), minimal stent area (MSA), and minimal lumen area (MLA) pre- and post-IVL application. Procedural success constituted the efficacy endpoint, while peri-procedural complications, in-hospital-30-days and long-term mortality, and MACE were safety endpoints Results This meta-analysis comprised 21 studies including 669 patients and 673 treated lesions in underexpanded stent. The mean age was 73.2 ± 2.1 years, with an overall IVL procedural success rate of 93% [(95% Confidence Interval (CI): 88%-96%, I2=29%), while the in-hospital-30-days and long-term mortality incidence were 1% (95% CI: 1%-3%, I2=0%) and 3% (95% CI: 2%-6%, I2=0), respectively. The 30-days target lesion revascularization (TLR) was approximately 6% (95% CI: 3%-12%, I2=50%). There was a significant increase in the MDS [Standardized Mean Difference (SMD): +50.52%, 95% CI: 39.4-61.6, I2=94%)] and in MSA (SMD: +3.52, 95% CI: 2.47 to -4.58, I2=83%) immediately after IVL application. It was observed a significant increase in MLD (SMD: +1.54, 95% CI: 1.09 to 1.98, I2=95%) and in the MLA (SMD: +3.64, 95% CI: 2.62-4.66, I2=5%). Major procedural and device related complications were 3% (95% CI: 1%-6%, I2=0%) and 1% (95% CI: 0%-2%, I2=85%) respectively. Notably low rates were observed for stent thrombosis (0%, 95% CI: 0%-2%, I2=0%), dissections (1%, 95% CI: 1%-4%, I2=0%), perforations (1%, 95% CI: 1%-3%, I2=0%) and no-reflow (0%, 95% CI: 0%-1%, I2=0%). Conclusions IVL demonstrates promise as a safe and effective strategy for underexpanded stent treatment, characterized by low rates of periprocedural complications. Future prospective studies are now warranted to compare IVL to other lesion preparation strategies.30day All-Cause Mortality after IVL use.Minimum Stent Diameter after IVL use.

Identification of the low resistivity-low contrast (LRLC) gas-bearing pay zones in Shaly sand reservoirs using acoustic data: a case study from the Messinian Abu Madi formation, onshore Nile Delta, Egypt

AbstractDetection of the low resistivity-low contrast (LRLC) reservoirs is among the main challenges in the oil industry. In this concern, the LRLC pay zones of the Upper Messinian Abu Madi clastic reservoirs in the onshore Nile Delta Gas fields became a main challenge for significant exploration. This type of reservoirs, including low resistivity-low contrast zones and thin-bedded intervals, are often overlooked using the conventional petrophysical evaluation techniques, especially in the wildcat exploratory wells or highly agitated shoreline depositional environments like the Nile Delta of Egypt. These hidden low contrast reservoirs are generally challenging due to the presence of many shale intercalations/laminations and/or due to increasing the shale volume represented in the form of dispersed distribution, and the dominance of conductive clay minerals. Therefore, in this study, the expected high resistivity values of the gas-bearing reservoir intervals of the Abu Madi Formation in the onshore Begonia gas Field, as a typical case study of the LRLC reservoirs, are masked due to the relatively high shale conductivity, particularly when the thickness of these intervals is less than the vertical resolution of the utilized conventional resistivity log. To verify the LRLC phenomena of the Begonia gas Field, the obtained data was compared to the South Abu El Naga gas Field as a normal case study with a relatively high resistivity gas-bearing pay zone. To overcome the impact of the conductive clay mineral content and identify these hidden low resistivity reservoir intervals, it is necessary to integrate the conventional logging data (gamma-ray, shallow and deep resistivity, density, and neutron) with the acoustic log data including shear and compressional sonic data. In this way, a useful relationship can be established enabling the detection of these hidden LRLC reservoir intervals. This integration is based on the principle that shear waves are not influenced by the fluids types, whereas the compressional sonic waves are influenced by the reservoir fluids. However, to effectively investigate these concealed LRLC reservoir intervals, which can boost production and increase the potential reserves, it is essential to have a low water cut value. The present study represents introduces an efficient workflow, which can be extended to other similar LRLC pay zones in the Nile Delta and northeast Africa. It is also extendible to the LRLC reservoirs in similar deltaic systems having conductive minerals-bearing reservoirs or thin beds.

Successful use of lithoplasty for re-expansion of covered iliac stents with unilateral occlusion.

Vessel wall calcification is associated with stent under-expansion and in-stent restenosis. The traditional approaches to treat peripheral artery calcification are percutaneous transluminal angioplasty (PTA) and atherectomy. Shockwave intravascular lithotripsy (IVL) uses sonic wave pressure to disrupt calcium of the severely calcified lesions. Published reports of IVL to treat in-stent restenosis are limited to coronary interventions and bare metal platforms. We describe the case of a 55-year-old male with extremely compressed under-expanded covered stents associated with severe wall calcification that resulted in stent occlusion. The IVL system balloon was deployed uneventfully, in a phased manner. Bilateral bare metal stents were also placed in a kissing fashion to further re-expand the arterial segments. Reintervention with IVL facilitated successful revascularization and the stent remained patent at 24 months. Our case highlights the use of IVL as an effective tool in the management of vessel wall calcification both for primary and secondary interventions.

Intravascular Lithotripsy: Approach to Advanced Calcified Coronary Artery Lesions, Current Understanding, and What Could Possibly Be Studied Next.

Calcified and resistant narrowing of arteries poses significant difficulty in performing percutaneous coronary interventions (PCIs), as they increase the risk of subpar outcomes leading to worse clinical outcomes. Despite the existence of dedicated technologies and devices, including various balloons and atherectomy systems, they often do not ensure sufficient plaque modification and ideal vessel preparation for optimal stent deployment. Intravascular lithotripsy (IVL), a technology originally developed for urological procedures, has recently been used to safely and selectively disrupt calcified depositions in both peripheral and coronary arteries by sonic waves that seamlessly transfer to nearby tissue, enhancing vessel compliance with minimal impact on soft tissues. In the coronary arteries, the use of IVL plays a role in the process of "vessel preparation" before the placement of stents, which is crucial for restoring blood flow in patients with severe coronary artery disease (CAD), and is considered a minimally invasive technique, reducing the need for open heart surgeries and associated risks and complications. Studies have shown that IVL can lead to improved procedural success rates and favorable long-term outcomes for patients with severely calcified coronary artery disease. With the advent of IVL, the disruption of severe calcification of coronary artery and stenotic lesions before stent implantations can be performed. Despite promising data for treating calcified lesions, IVL is significantly underutilized in clinical practice, long-term clinical data and extensive research are needed to validate its further safety and efficacy. In this article, we reviewed the literature discussing the use of IVL in the coronary arteries as an approach for addressing intravascular atherosclerotic plaques, particularly focusing on heavily calcified plaques that are resistant to standard initial PCI, while also evaluating its safety in comparison to alternative methods.

Intravascular lithotripsy in peripheral lesions with severe calcification and its use in TAVI procedure - a meta-analysis.

Background: Heavily calcified peripheral artery lesions increase the risk of vascular complications, constituting a severe challenge for the operator during catheter-based cardiovascular interventions. Intravascular Lithotripsy (IVL) technology disrupts subendothelial calcification by using localized pulsative sonic pressure waves and represents a promising technique for plaque modification in patients with severe calcification in peripheral arteries. Purpose: Our aim was to systematically review and summarize available data regarding the safety and efficacy of IVL in preparing severely calcified peripheral arteries and its use in Transcatheter Aortic Valve Implantation (TAVI). Patients and methods: This study was conducted according to the PRISMA guidelines. We systematically searched PubMed, SCOPUS, and Cochrane databases from their inception to February 23, 2023, for studies assessing the characteristics and outcomes of patients undergoing IVL in the peripheral vasculature. The diameter of the vessel lumen before and after IVL was estimated. The occurrence of peri-procedural complications was assessed using a random-effects model. Results: 20 studies with a total of 1,223 patients with heavily calcified peripheral lesions were analysed. The mean age of the cohort was 70.6 ± 17.4 years. Successful IVL delivery achieved in 100% (95% CI: 100%-100%, I2 = 0%), with an increase in the luminal diameter (SMD: 4.66, 95% CI: 3.41-5.92, I2 = 90.8%) and reduction in diameter stenosis (SMD: -4.15, 95% CI: -4.75 to -3.55, I2 = 92.8%), and a concomitant low rate of complications. The procedure was free from dissection in 97% (95% CI: 91%-100%, I2 = 81.4%) while dissections of any type (A, B, C, or D) were observed in 6% (95% CI: 2%-10%, I2 = 85.3%) of the patients. Several rare cases of abrupt closure, no-reflow phenomenon, perforation, thrombus formation, and distal embolization were recorded. Finally, the subgroup analysis of patients who underwent a TAVI with IVL assistance presented successful implantation in 100% (95% CI: 100%-100%, I2 = 0%) of the cases, with only 4% (95% CI: 0%-12%, I2 = 68.96%) presenting dissections of any sort. Conclusions: IVL seems to be an effective and safe technique for modifying severely calcified lesions in peripheral arteries and it is a promising modality in TAVI settings. Future prospective studies are needed to validate our results.

Evaluation of Sonic Boom Shock Wave Generation with CFD Green Methods

Over the past two decades, there has been a renewed interest in the development of a new generation of supersonic aircraft for civil purposes that could potentially succeed Concorde. However, the noise annoyance is still considered one of the hampering factors to meet public consensus. This paper aims at revealing the potential of numerical simulations to predict sonic boom signature in Near Field at early design stages. In particular, the paper further demonstrates the applicability of the numerical approach proposed by NASA and other partners during the Sonic Boom Prediction Workshops held between 2014 and 2021, to compute the pressure signature of aircraft in the zone close to it. The results highlight the suitability of the approach (1) to capture the impact of aircraft flight condition variations on the sonic boom signature, (2) to enable the characterization of novel aircraft layout, including Mach 5 waverider configuration, (3) to provide near-field shock wave noise predictions that can be used to evaluate shock propagation, on-ground signature analyses, and annoyance assessment.

Machine learning assisted Kriging to capture spatial variability in petrophysical property modelling

Machine learning (ML) models have been widely used for estimating formation geophysical properties. While ML models excel at capturing non-linear correlations among parameters, incorporating the impact of spatial variability into the training and testing process remains challenging. On the other hand, deterministic geostatistical models such as Kriging are capable of capturing spatial variability to a great extent but often rely on the assumption of linearity, making them less suitable for non-linear relations. In this study, a machine learning (Least Squared Support Vector Regression, LSSVR) model is integrated into Kriging interpolation to estimate the sonic compressional wave velocity with high spatial variability over a geological setting. This new methodology consists of two steps: (1) constructing an initial machine learning model using LSSVR and calculating the residuals, and (2) applying Kriging interpolation and gradually modifying the training data using Kriging estimation to optimize the machine learning model. The proposed model effectively captures the non-linear relation between auxiliary and target variables along with the spatial autocorrelation of data. To evaluate the performance of proposed hybrid model, a dataset comprising geophysical downhole logging measurements including density, gamma ray, depth and sonic velocity were extracted from 122 boreholes in a mine site located at the Bowen basin in Queensland, Australia. The data was averaged over a sandstone interval and divided into training and testing sets. Four models, namely linear regression, regression Kriging, LSSVR and the hybrid model were developed and compared with each other based on their R2 and RMSE values. The results demonstrate that the hybrid model outperforms the other models highlighting the effectiveness of employing a hybrid approach in capturing the spatial variability in petrophysical data over geological formations.

Beyond waste: waste rice husk to value-added products using sonic waves and chemical treatment and principal component analysis of extraction

Beyond waste: waste rice husk to value-added products using sonic waves and chemical treatment and principal component analysis of extraction

Application of the CABARET and WENO Schemes for Solving the Nonlinear Transport Equation in the Problem of Simulating the Propagation of a Sonic Boom Wave in the Atmosphere

Application of the CABARET and WENO Schemes for Solving the Nonlinear Transport Equation in the Problem of Simulating the Propagation of a Sonic Boom Wave in the Atmosphere

Volve Oil Field S-Wave Log Data Prediction Using GBR and MLPR

The shear wave sonic (S-wave) log data is essential for identifying the reservoir's geomechanical properties, which is an important factor for the drilling, completion, and optimization processes, where obtaining S-wave requires capital investment and reduces the cost. In this paper, we used the multi-layer perceptron (MLPR) and the gradient boosting regression (GBR) to predict the missing S-Wave log data for the Volve Oil Field in the North Sea. Prescriptive and predictive analysis were carried out in series to achieve a high blind data accuracy rate of 0.943 and 0.982 for the multi-layer perceptron regression and the gradient boosting regression, respectively. It was observed that the gradient-boosting algorithm achieved higher accuracy than the MLPR algorithm for the limited dataset. It was also found that hierarchical clustering can reveal information regarding the feature's importance similar to the relevant AI tools, which makes hierarchical clustering a faster tool in eliminating the nonimportant inputs from the dataset while the use of artificial intelligence tools showed a significant effect in predicting the missing values of the sonic wave log and the neutron porosity log in an efficient way by selecting the relevant important features.

Anisotropy and compaction gradient assessment on rammed earth specimens through sonic tomography approach

Rammed earth is a traditional construction technique that has recently gained attention because of its benefits from an ecological perspective. The conservation of the existing valuable cultural heritage sites and the quality control of new constructions built with this material require the development and application of practical inspection techniques. This paper explores the application of sonic tests and sonic tomography as practical tools for monitoring the state of conservation of existing structures and the identification of heterogeneities or damaged areas. Two groups of 6 rammed earth specimens were manufactured and tested. The manufacturing process of each group allowed the application of compression loads and the identification of the Sonic Wave Propagation Velocities along directions parallel and perpendicular to the compaction forces during manufacturing. The SWPV were identified for the different paths between 9 measuring points located at two opposite sides of the specimens, leading to up to 6 different planes for each specimen. The SWPV are identified by identifying the Time-of-Flight of the elastic wave between each pair of excitation and receiver points. A discretized coloured map of the SWPV distribution for each plane defined by the measurement points array is obtained by the application of an algorithm already developed by the authors to obtain tomographic images for other materials and applications. The SWPV are identified after 2 different increasing values of a uniform compressive load is applied to each specimen. The results show that the analysis of the SWPV and tomographic images is sensitive to heterogeneities, such as compaction gradients from the manufacturing process, and also to the accumulated damage in the solid. The paper demonstrates that the proposed technique can be potentially used for a qualitative inspection of the state of conservation of specific rammed earth constructions.

Efficacy of intravascular lithotripsy (IVL) in coronary stenosis with severe calcification: A multicenter systematic review and meta-analysis.

With heavily calcified coronary and peripheral artery lesions, lesion preparation is crucial before stent placement to avoid underexpansion, associated with stent thrombosis or restenosis and patency failure in the long-term. Intravascular lithotripsy (IVL) technology disrupts superficial and deep calcium by using localized pulsative sonic pressure waves, making it to a promising tool for patients with severe calcification in coronary bed. The aim of the study is to systematically review and summarize available data regarding the safety and efficacy of IVL for lesion preparation in severely calcified coronary arteries before stenting. This study was conducted according to the PRISMA guidelines. We systematically searched PubMed, SCOPUS, and Cochrane databases from their inception to February 23, 2023, for studies assessing the characteristics and outcomes of patients undergoing IVL before stent implantation. The diameter of the vessel lumen before and after IVL, as well as stent implantation, were analyzed. The occurrence of major adverse cardiovascular events (MACE) was assessed using a random-effects model. This meta-analysis comprised 38 studies including 2977 patients with heavily calcified coronary lesions. The mean age was 72.2 ± 9.1 years, with an overall IVL clinical success of 93% (95% confidence interval [CI]: 91%-95%, I2 = 0%) and procedural success rate of 97% (95% CI: 95%-98%, I2 = 73.7%), while the in-hospital and 30-days incidence of MACE, myocardial infarction (MI), and death were 8% (95% CI: 6%-11%, I2 = 84.5%), 5% (95% CI: 2%-8%, I2 = 85.6%), and 2% (95% CI: 1%-3%, I2 = 69.3%), respectively. There was a significant increase in the vessel diameter (standardized mean difference [SMD]: 2.47, 95% CI: 1.77-3.17, I2 = 96%)and a decrease in diameter stenosis (SMD: -3.44, 95% CI: -4.36 to -2.52, I2 = 97.5%) immediately after IVL application, while it was observed further reduction in diameter stenosis (SMD: -6.57, 95% CI: -7.43 to -5.72, I2 = 95.8%) and increase in the vessel diameter (SMD: 4.37, 95% CI: 3.63-5.12, I2 = 96.7%) and the calculated lumen area (SMD: 3.23, 95% CI: 2.10-4.37, I2 = 98%), after stent implantation. The mean acute luminal gain following IVL and stent implantation was estimated to be 1.27 ± 0.6and 1.94 ± 1.1 mm, respectively. Periprocedural complications were rare, with just a few cases of perforations, dissection, or no-reflow phenomena recorded. IVL seems to be a safe and effective strategy for lesion preparation in severely calcified lesions before stent implantation in coronary arteries. Future prospective studies are now warranted to compare IVL to other lesion preparation strategies.

Mixing dynamics in the synthesis of nanoparticle-stabilized water-in-water emulsion: Impact on size and stability

This communication presents a comprehensive investigation into the impact of mixing on the synthesis of water-in-water Pickering emulsions. The approach employs commercial-grade oppositely charged nanoparticles within two distinct fluid phases, facilitating self-assembly and the formation of aggregates with variable sizes and compositions. Enhanced interfacial area, achieved through aggregate adsorption at the interface, elevates the Gibbs detachment energy of particles between the two aqueous phases, leading to stable emulsion formation. We further explore the effect of various mixing devices, including high-pressure and sonic wave mixing. Our findings reveal that mixing within the aqueous phase critically influences emulsion size, with sonicator-assisted mixing producing smaller droplets than homogenizer mixing. Both devices yield poly-dispersed droplet size distributions. Interestingly, the droplet size correlates well with the Hinze scale (hd), and the Kolmogorov length scale (ld) exhibits good correspondence within a specific operating range. The proposed method introduces a streamlined, one-step synthesis process for easy preparation, demonstrating excellent stability for a minimum of 30 days. This study pioneers the investigation of mixing effects within an aqueous two-phase system utilizing a Pickering emulsion template.

Mechanical behaviour and microstructure of methane hydrate-bearing sandy sediment observed at various spatial scales

Methane hydrates (MHs) are considered an alternative energy resource but also a potential source of geo-hazards and climate change. The physical/mechanical properties of gas hydrate-bearing sandy sediments are strongly dependent on the distribution of hydrates within the pore space. The purpose of this study is to investigate morphologies and pore-habits of MHs formed in sandy sediments by means of experiments that probe a wide range of scales, from the pore scale – using Synchrotron X-Ray Computed Tomography (SXRCT) and optical microscopy – to the core scale, through mechanical property measurements. The same synthetic sands are used, in which MHs are generated successively under excess gas and excess water conditions. At the macroscopic (core) scale, MH pore habits are inferred by comparing the measured sonic wave velocities to velocities calculated from rock physics models and further assessed via triaxial compression tests. Furthermore, Magnetic Resonance Imaging is used to investigate the kinetics of MH formation and distribution along the core height. The pore habits and MH morphologies are directly visualized at the pore (grain) scale by SXRCT and, with still better spatial and temporal resolution, by transmission optical microscopy, revealing some more complex morphologies than in the hydrate pore habits commonly admitted.

Optimizing Neural Network Efficiency by Neuron Pruning

This study primarily focuses on two main objectives. The primary objective is to develop an appropriate model for accurately predicting the missing shear wave data in the Volve Oil Field located in the North Sea. By employing the Multi-Layer Perceptron Regression and modifying the neural network structure, the first goal attains a prediction accuracy of 0.943 for missing S-Wave log data. Furthermore, the objective of the study is to enhance the precision of forecasting incomplete S-Wave log data by optimising the structure of the artificial neural network, using neuron pruning techniques based on sensitivity analysis. This optimisation leads to a heightened accuracy rate of 0.9609. The effectiveness of these pruning strategies is clearly evident in their demonstrated capacity to improve the accurate prediction of missing data in the sonic wave log.

Effect of the sonic shock wave on void evolution in materials under irradiation

Understanding the void-cascade interaction is of great importance for clarifying the irradiation damage as a major challenge in nuclear industry, since it typically causes void annihilation or shrinkage, which greatly affects the swelling of irradiated materials. But the current understanding of it is extremely limited due to the neglect of the sonic shock wave. Herein, we take γ-U as the representative model due to the emergence of a violent sonic shock wave there. Molecular dynamics simulations are performed to explore the underlying mechanism of the sonic shock wave interacting with voids. It is firstly revealed that the sonic shock wave is essentially focusons along <111> crystal orientation family, attributed to the highest energy transfer efficiency along <111> in γ-U. These focusons can cause void annihilation or shrinkage via sliding, while thermal spikes only cause annihilation by covering voids. Combining these two factors, we propose a model to qualitatively epitomize the void-cascade interaction, in which the influence scope exhibits an intriguing anisotropic feature, overturning a long-accepted view that the void-cascade interaction is isotropic. This model is further generalized to other nuclear materials owing to the similar mechanism of the sonic shock wave. Moreover, we find distinct size effect of voids on void-cascade interaction. Thermal spikes hardly affect voids that are too large to be covered, while the sonic shock wave also causes visible shrinkage in large voids. The present work proves that the sonic shock wave has a non-negligible effect on void evolution, improving the fundamental understanding of void-cascade interaction in irradiated materials.

Acoustic valley Hall topological insulators with controllable band gap

In recent years, numerous studies have investigated the impact of imperfections on topological insulators, and certain defects have been observed. Former topological insulators have a limited range of topological transport bands and an irregular lattice structure, which hampers their usefulness in technological applications. Here, it’s implemented the topological transport of sonic waves in a phononic crystal array structure. This paper has shown that changing the rotating scatterer's angle can alter the topological phase, resulting in lattice band inversion. This establishes a topological channel that enables acoustic conduction. It is feasible to create multifarious channel structures and devise acoustic transmission systems with varying positions. The introduction of rotating scatterers enables the regulation of the influx of acoustic waves into targeted channels. And the robustness of its edge states was verified by using the finite element method. These outcomes furnish the sound wave control mechanism with a novel formation and urge the development of programmable sound wave regulation. Based on these properties, the technique of regulating topological wave propagation through the use of a topological insulator can also be extended to other systems, including filters and acoustic devices.

WITHDRAWN: The impact of stylolitization on the elastic properties of carbonate reservoirs using laboratory measurements

Stylolitization is one of the most important sedimentary features occurring during diagenetic processes in carbonate rocks. This study experimentally explored how stylolitization and stylolite types affect the elastic behavior of carbonate rocks using hydrostatic tests and ultrasonic measurements. Moreover, petrophysical and well data, including logs (image logs, density, porosity, compressional sonic wave, and shear sonic wave), and Computed Tomography (CT) scans have been used for the selection of appropriate plugs and stylolite classification based on their morphological properties. The observed stylolites were subdivided into four groups: rectangular, seismogram, suture (sharp), and wave-like. To develop new insight into the relationship between stylolites and elastic properties, hydrostatic laboratory tests were conducted under two different saturation conditions: drained (zero pore pressure) and undrained (constant pore pressure). Our results indicate that stylolite-free samples have higher porosity, which suggests that they may have lower velocities. Furthermore, we observed that the stylolitified samples had a higher gradient of VP changes compared with the VS changes, with a strong dependency on the stress state variations (confining and effective pressures). These samples have more potential to contain crack porosities than stylolite-free samples, and stylolites may act as weak surfaces. These weak surfaces can cause different velocity behaviors in the stylolite-bearing samples at low and high pressures (room and reservoir pressures). Our findings indicate that the opening or filling material within the stylolites may have contributed to the increase or decrease in the sonic velocities. If the stylolites are open, then their behaviors are similar to those of crack porosities and can decrease the velocities. However, the filled stylolites showed a positive effect on the velocities depending on the filling materials, which were dense. Finally, this study presents a mechanical anisotropy analysis to identify the origin and type of stylolite.

Rotational Atherectomy, Orbital Atherectomy, and Intravascular Lithotripsy Comparison for Calcified Coronary Lesions.

In order to improve the percutaneous treatment of coronary artery calcifications (CAC) before stent implantation, methods such as rotational atherectomy (RA), orbital atherectomy (OA), and coronary intravascular lithotripsy (IVL) were invented. These techniques use different mechanisms of action and therefore have various short- and long-term outcomes. IVL employs sonic waves to modify CAC, whereas RA and OA use a rapidly rotating burr or crown. These methods have specific advantages and limitations, regarding their cost-efficiency, the movement of the device, their usefulness given the individual anatomy of both the lesion and the vessel, and the risk of specified complications. This study reviews the key findings of peer-reviewed articles available on Google Scholar with the keywords RA, OA, and IVL. Based on the collected data, successful stent delivery was assessed as 97.7% for OA, 92.4% for IVL, and 92.5% for RA, and 30-day prevalence of MACE (Major Adverse Cardiac Events) in OA-10.4%, IVL-7.2%, and RA-5%. There were no significant differences in the 1-year MACE. Compared to RA, OA and IVL are cost-effective approaches, but this is substantially dependent on the reimbursement system of the particular country. There is no standard method of CAC modification; therefore, a tailor-made approach is required.

Superwavelength self-healing of spoof surface sonic Airy-Talbot waves

Self-imaging phenomena for nonperiodic waves along a parabolic trajectory encompass both the Talbot effect and the accelerating Airy beams. Beyond the ability to guide waves along a bent trajectory, the self-imaging component offers invaluable advantages to lensless imaging comprising periodic repetition of planar field distributions. In order to circumvent thermoviscous and diffraction effects, we structure subwavelength resonators in an acoustically impenetrable surface supporting spoof surface acoustic waves (SSAWs) to provide highly confined Airy-Talbot effect, extending Talbot distances along the propagation path and compressing subwavelength lobes in the perpendicular direction. From a linear array of loudspeakers, we judiciously control the amplitude and phase of the SSAWs above the structured surface and quantitatively evaluate the self-healing performance of the Airy-Talbot effect by demonstrating how the distinctive scattering patterns remain largely unaffected against superwavelength obstacles. Furthermore, we introduce a new mechanism utilizing subwavelength Airy beam as a coding/decoding degree of freedom for acoustic communication with high information density comprising robust transport of encoded signals.